Selector switch for telephonic or other commutation systems



E. ALIZON Jan. 19, 1954 SELECTOR SWITCH FOR TELEPHONIC OR OTHERCOMMUTATION SYSTEMS Filed April 3, 1950 u l 4 T 7 0 m 1 v I J. w M m m aF F e h s a 4 My 5 fwd L m7 ME Q m Fig.6

1' I/VE/WOR m w s 00mm U MM Amm n T E W Jan. 19, 1954 E. ALIZON2,666,811

SELECTOR SWITCH FOR TELEPHONIC OR OTHER COMMUTATION SYSTEMS Filed April5, 1950 4 Sheets-Sheet 2 llllllllllll! W N 6. W 7. 6 w WWW w I a ,1 4 l"w m 7 m? ma w Z LLLLLL LLLLLL 21:11:: 57:51.- I.

HHIIIIIIIII lllllllllllll Jan. 19, 1954 E. ALIZON 2,666,811

SELECTOR SWITCH FOR TELEPHONIC OR OTHER COMMUTATION SYSTEMS Filed April3, 1950 1 4 Sheets-Sheet 5 ImvEmrm EfiEmn E Quinn) Jan. 19, 1954 ALIZON2,666,811

SELECTOR SWITCH FOR TELEPHONIC OR OTHER CQMMUTATION SYSTEMS Filed April3, 1950 4 Sheets-Sheet 4 RECORD/N6 MEANS M WV B 4- 1W Patented Jan. 19,1954 SELECTOR SWITCH FOR TELEPHONIC OR OTHER COMMUTATI-ON SYSTEMSEtienne Alizon, La Celle Saint-Cloud, France a f Application April 3,1950, Serial No. 153,594 I V Claims priority, application France April6, 1949 '1 Claims. (01. 179-2751) The present invention relates torotary selector switches for use in automatic telephone exchanges andthe like, and more particularly to selector switches for use in systemswherein line finding is accomplished by .capacitive testing, without theuse of galvanic contact between elements of the selector incoming lineand elements of the various outgoing lines of the selector.

Selectors are known in which, when the selector is free, the brushesconnected to the incoming line are at rest with respect to thestationary contacts of the selector outgoing lines.

These brushes are mounted on a rotor and are set in motion when theselector operates to find a line. The brushes are then stopped againstthe contacts of the desired outgoing line in order to connect suchdesired outgoing line to the incoming line of the selector.

In some known selector systems (cf. French incoming line, galvaniccontact being established only when the selection is made.

Even in these known systems however it is stillnecessary that at leastone rotor brush have frictional contact with the stator contacts of itsrow,,and that at leastthe rotor incoming line contact connectedto thatbrush havevfric tional contact with its associated fixed incoming linecontact.

For, if the desired outgoing line is identified by a particular electricstate of the contact pins of one or]. morev rows of stator outgoing linecontacts, this electric state must be transmitted to the device whichgoverns motion of the selector by means of precisely such contact Ifinstead accordingto' another known form of construction the selectoroperates step by step so that the desired outgoing line is identified bythe number of steps executed by the brushes in starting from a zeroposition, it is still necessary that at least. one rotor brush possessgalvanic contact with the outgoing line stator contacts of the statorrow associated with that brush and that the incoming line rotorelectrode connected to that brush possess galvanic contact with theincoming 'hnestator contact 'AasSociated therewith in order to ensure asystematic return of the rotor to its zero position when the selector isreleased.

These frictional contacts, even when thus restricted to a small numberof the elements of the selector, consume energy and are a cause of wear.If the contact pressures are reduced to minimize these mechanicaldisadvantages, the resultant electrical contact is unsatisfactory.

The present invention provides a rotary selector with semicircular rowsof outgoing line stator contacts arrayed one above another into asemicylindrical surface and in which the rotor scanning brushes whichexplore the panel of stator outgoing line contacts so formed areincorpor ated into a rotor which moves at uniform velocity with respectto the stator when the selector is free. The rotation is stopped whenthe selector makes selection of adesired outgoing line. During rotationthe rotor scanning brushes travel past the outgoing line stator contactswithout mechanical contact therewith. These scanning brushes areconnected within the rotor to incoming line rotor electrodes, pref--erably of approximately circular shape, which are capacitivelyassociated and not mechanically connected during such rotation withstator electrodes connected to the wires of the selector incoming line.In the course of a selection, characteristic voltages applied toselected stator contacts of each outgoing'line are capacitively inducedupon the rotor scanning brushes which move past them, and thesepotentials are then capacitively passed from the rotor incominglinerotor contacts; are; brought into galvanic contact with appropriateoutgoing line contact pins in the stator. At the same time the rotorincoming line electrodes are brought by axial translation of the rotorinto firm galvanic con-' tact with stator incoming line contacts so asto effect galvanic contact between the respective wires of the selectorincoming line and those of the chosen outgoing line.

Upon the iden-I With the con-, struction of the invention, to" bedescribed in further detail below,- the contactypressures obtained afterselection are much higher than those available in rotary selectors ofthe prior art. Moreover, according to the invention certain contactauxiliary to the talking circuit to be established are made or brokenwithout the help of relays or other auxiliary devices. For exampleadvantage is taken of the axial motion of the selector rotor upon themaking of a selection to provide directly a holding circuit for thestopping coil by means of which the rotor .is stopped and held in fixedposition once the desired outgoing line has beenhfoun'd.

Because of the indeterminate values Ofthe wiring capacities involved,the voltages transmitted from a selector according to the invention tothe input terminals of an identification means as described above willnot in general be a constant fraction of the characteristicidentification volt ages applied to the selector outgoing line statorcontacts. Within the identification means therefore theline-characteristic identification volt.- agescan therefore beidentifieddependably only by their polarity, in the case of'D. C. voltages, or bytheir frequency in the case of A. C. voltages. Since D. C.'voltages thuspossess only three characteristic values: positive, zero and negative,they would'permit selection of only a restricted number of lines or linegroups.

If more than two or three lines or line groups are to be identified, itis therefore necessary to employ A. C. identification voltages. Thiswill usually be the case for selectors employed as either groupselectors or final selectors. In an exchange therefore, for which theselectors of the invention are designed, each outgoing line or linegroup is identified by a particular frequency or frequencies of theidentification voltages which are applied to one or more of the statorcontacts of that line as it appears as an outgoing line of a selectoraccording to the invention. To set up a desired circuit the selectorrotor is stopped to effect galvanic connection between the wires of theselector incoming line and the wires of a free outgoing line thecharacteristic frequency or frequencies of which have been determined tobe identical to a predetermined reference frequency or frequencies,chosen by a recorder or sender storing the signals generated by acalling subscribers dial, for example. In

my copending application Serial No. 208,794, filed January 31', 1951, Ihave described frequency identification means ha-ving two inputterminals to which are applied A. C. voltages of varying frequency andhaving an output across which there is developed a D. C. voltage signalwhen and only when the input voltages are of the same frequency.

In'order for'such identification means to be able dependably to identifythe frequencies of the voltages scanned from the outgoing line statorelectrodes, it is necessary that the period of the lowestidentification.frequency employed be short compared to .the time'required for thepassage of the rotor scanningbrush past one of the stator electrodesheld to. such an identification voltage. For this reason and further to.prevent disturbance of the actualcommunication channels by suchidentification-voltages,tthe. latter are all selected above the 'audiorange, and preferably above 10 kilocycles.

The use of. such high frequencies for the identification voltagesrequires that precautions be taken to minimize their mixing bycapacitive induction among the wires of the various outgoin lines whichcarry these voltages to the stator contacts of thesele tors, of.theinvention. .In

particular, the multiplying together of a plurality of selectors bymeans of flat fan-shaped groups of wires radiating in each selector fromthe contacts of a single semicircular row cannot be employed since itdoes not permit the use of proper electrostatic shielding to preventsuch induction. For, even with electrostatic shields between theadjacent fan-shaped hundleatlie wires of each bundle constitute wires ofa single function drawn from a large number of outgoing lines, andcertain bundles would precisely combine together ,thewires ;o'fsa:;plurality of outgoing lines held to the differentidentification voltagefrequencies of those lines. According to the invention there- 'foremultiplying 'wires are grouped not according tov function-hut accordingto azimuth, bringing together all the wires of one outgoing line or ofthe *srnallnumber of outgoing lines whose contacts occupy a singleazimuthal position or vertical row in the selector stator. The bundlesare therefore made up parallel to the selector axis ratherthanperpendicular thereto.

The invention will now be further described in detail with referencetothe accompanying drawings. in which:

Fig. 1. ista view insideelevation'of the outgoing line statorelements'ota single azimuth of a plurality of selectors according to theinvention, multipliedtogether;

Fig. 2 .is a plan view from above of the lower stator fiange or framemember of a'selector according to the invention;

Fig. 3 is a view in side-elevation of the flange of Fig. 2 as seen fromtheleft in Fig. 2;

Fig. 4 is a plan view from below of the upper stator flange or framemember of a selector according to the invention;

Fig. 5 is a view in side elevation of the flange of Fig. 4 seen fromth'e'right in Fig. 4;

Fig. 6 is a view inside elevation of the outgoing line statorelements'of a single azimuth of a selector accordingto the inventionprior to their envelopment in an insulating plastic material;

Fig. '7 is a view similar to that of Fig. 6 showing the assembly of theoutgoing line stator elements for a single azimuth of a selector aftertheir envelopment in a plastic coating Fig. 8 is an endelevat'ional viewof the assembly of Fig. 7;

Fig. 9 is a --viewinside 'elevation'of a wedge employed to space andfasten into a selector two adjacent azimuth assemblies according toFigs. 6, 7 and 8;

Fig. 10 is a plan view 'of the wedge of Fig. 9;

Fig. 11 is a view in side elevation of th outgoing line statorbanks of aplurality of selectors according to the invention multiplied to.- getherand combine'd'linto "a column seen from the concave side;

Fig. 12 is. a view ini'side'elevation of one of the banks of'Fig. 11,seen-fromthe left in Fig. 11;

Fig. 13' is a sectional view taken on the line l3-|3 of Fig.'11;

Fig. 14 Ba viewinsideelevation of a single selector according to theinvention, this view being similar to that oiFig. .1.11(for oneselector) except that me selectorro'tor'and fixed incomingline'elementsrareishown; H

Fig. 15 is a sectional view'taken on the line b-b of Fig..14, seen frombelow;

Fig. 16 is :a sectional viewtalien on the line.

c c-of Fig. 15, showing the. removable elements of the selectorincluding the rotor, the rotor stopping means, and the fixedincomingline elements;

Fig. 17 1s .a perspective view sof .therotoristopping means and of theselector incoming line electrodes and contacts, viewed in the directionof the arrow d in Figs. 14 and 15;

Fig. 18 is a detailed view of part of the rotor outgoing line brushcarrying structure of the rotor shown in Fig. 16, taken in the directionof the arrow 9 and between the planes indicated at e and fin Fig. 16;

Fig. 19 is a schematic view of the rotor elements of a selectoraccording to the invention With the stator elements for a singleazimuth, shown in connectionwith certain other elements of a switchingsystem with which the selector of the invention is adapted to cooperate,and

Fig. 20 is a partial sectional view in plan of a selector according tothe invention showing the outgoing line stator contacts and electrodesof two horizontal rows in the stator bank and the rotor brushes andcontacts which cooperate therewith.

As is illustrated in Figs. 1 and 11 the selectors of the invention areadapted to be combined into columns of selectors which are multipledtogether according to well-known principles. Figs. 1 and 11 showelements of four selectors only. A large number of selectors may ofcourse be provided in the column.

The stator of each selector includes flange or frame members 2 and 3 asillustrated in Figs. 2 and 4 supporting a plurality of outgoing linestator contact assemblies lil of the type illustrated in Figs. 7 and 8.-Each selector further includes stationary elements associated with theselector. incoming line and a rotor adapted to effect contact betweenthe wires of the selector incoming line and the wires of any one of theoutgoing lines which is brought to the selector via one of theassemblies Ill. The rotor, rotor drive and rotor stopping mechanism(Fig. 16), and the stationary incoming line elements (Fig. 17) areremovably associable with the frame members 2 and 3 in which the bank ofstator outgoing line contacts are fastened. The assemblies l aredisposed in a semicircular array, each assembly defining an azimuth forthe selector stator. In the embodiment illustrated each assembly [0includes contacts and identification frequency electrodes for twooutgoing lines.

Referring now to Fig. 6, each assembly I 0 is I composed of a parallelarray of multipling wires 4, an insulating plate 5 and a plurality oftransverse bars some of which terminate in galvanic contact pins 8 andthe remainder of which terminate in scanning electrodes 1 perpendicularto the length of the wires 4, the aggregate number of the bars beingequal to the number of multipling wires 4. In the example illustratedthere are provided eight pin-shaped terminals 8 and six electrodes 1,having the form and function of condenser plates. The insulating plates5 are perforated so as to give one access to each of the multiplingwires 4 and each of the bars makes electrical contact with one of thewires 4 through such a perforation. The junctions are suitably solderedor welded to ensure good electrical contact. The bars are preferablymade of a material such as Phosphor bronze havinggood mechanical as wellas electrically conducting properties. Away from their ends I and 8 theymay be scored as shown to improve their adhesion in the envelopingplastic. The combination of the wires 4, plate 5 and transverse bars isthen suitably laminated or embedded in an insulating material such aspolymethacrylate to form an assembly!!! of rectangular section as shownin Figs. 7 and 8. customarily for economy of construction the wires '4are made of a length suitable to the number of; selectors to be builtinto the column desired sof that a series 1 of assemblies ID are formedintegrally together, the number of assemblies in inthe series beingequal to the number of selectorsfto be provided in the column.

Referring to Figs. 2 tot, the flanges 2 and 3, which may for example bedie cast of an aluminum alloy, are provided with a plurality of radialslots l2 between fingers M, the number of slots being equal to thenumber of assemblies H] to be provided in the selector. In theembodiment shown, fifty slots areiarranged over a semicircular arc, eachslot accommodating an assembly [0 which gives access toitwo outgoinglines.

A column of selectors is. assembled by fastening a double plurality ofthe flanges 2 and 3 in suitable order to frame members such as angleirons l8 (Fig. 13). The series 1 of assemblies If] as fragmentarilyillustrated in Fig. 1 are then inserted into the slots l2. The plasticcoating in which the assemblies l9" are embedded may be provided withgrooves H adapted to fit over the upper and lower flanges of eachselector to provide suitable mechanical rigidity.

To prevent crosstalk electrostatic shielding is provided betweenadjacent assemblies [0 by means of thin metallic foils 48 (Fig. 13)applied to one face of each of the entire series of assemblies [0 beforeinsertion into the flanges. Precautions are then taken to ensure goodelectrical contact between the foils 48 and the fingers I4 in theflanges to provide multiple ground points for the foils. Wedges l3 maybe inserted with the assemblies 10 in the slots l2. These areparticularly helpful where the assemblies are made of rectangularsection, as in the embodiment shown in Figs. 7 and 8.

The aspect of the resulting column of selector outgoing line elementsisillustrated in Figs. 11 through 13 in which for simplicity only asmall number of the contacts, foils and multipling wires have beenshown.

Figs. 14 and 15 illustrate a complete selector according to theinvention. This includes not only the bank of outgoing line statorelements hitherto described but also the incoming line stator elements,the rotor by means of which selection and contact between the incomingline and a chosen outgoing line is made, and the rotor driving andstopping means. The multipling wires 4 have been omitted from Fig. 15.

In addition to the outgoing line stator ele ments, formed into banks-asshown in Fig. 11, the selector of the invention comprises an incomingline stator contact assembly 30, a rotor 20, a driving mechanism 2!and-a rotor stopping mechanism l9, all illustrated in Fig. 16. Thestopping mechanism l9 comprises a plate 22, a cup 23, and a male cone 24all concentric with each other and forming together a magnetic circuitadapted to be energized by a rotor stopping coil winding 35. The cup 23is secured to the plate 22 by means of screws 25 and the cone 24 issecured" thereto by means of screws 26. The plate and cup may be splitas at 36 in Fig. 17 to reduce eddy currents. Over one half of itscircumference the plate 22 has the same radius as the cup 23 but overthe remainder of its circumference its radius is slightly greater,providing a supporting flange 21 terminating at abutments 28 located onopposite ends of a diameter of the plate .22. The.

flange (21 is employed tosupport the: stopping mechanism I9, incomingline contact assembly 30, rotor 20: and driving mechanism 2| from theframe 3, where. it fits into a semicircular groove I2 in which it isheld by a semicircular ring I3 (Figs. 4 and 14). .The elements 22, 23and 24 are made of soft iron. The stopping mechanism I9 supports theincoming line stator contact as.-

sembly 30 comprising a block 430 of insulatingmaterialon whichare'supported-the incoming line stator contacts of the selector (Figs.16 and 17). These contacts (shown schematically in Fig. 19) take theform of a plurality of semicircular rings 3|, I3I, 23I and 33Iconcentric with each other and with the axis 403 of the selector. Therings 3I, I3I, 23I and 33I are axially separatedand 'furtherinclude orhave respectively connected thereto, radially extending contact blades32, I32, 232 and 332 for the making of galvanic contact with the rotorincoming line contacts as willbe subsequently described. In addition,auxiliarycontact blades-233 and 333 on block 430 form intermittentcontacts with the blades 232 and. 332. Thus 232 and 233 form a pair ofnormally closed contacts, i. e. closed during rotation of the selector.The elements 332 and 333 form a pair of normally open contacts which areclosed only upon the axial translation of the selector rotor whichoccurs when selection ismade. The semicircular rings 3 I, I3I, 23I and33I and the blades 233 and '333 are provided with extensions 34' (Fig.17) to permit theattachment of conductors in any usual andsuitablemanner.

Referring now to Figs. 14, 15, 16 and 19 the selector rotor20 comprisesa molded plastic mem ber.83 of rotationally symmetric shape. likecylindrical portion 39 fits with clearance at bore 439 over theselectordrive shaft 63' and supports a soft iron female cone 4!) whichcompletes the magnetic circuitwith the cup 23 and the male cone '24. Thestem 39 further supports rotor incoming line contacts in the form ofcircular rings 4I, I4I, 24I and MI for capacitive and galvanicassociation with the incoming line stator rings and contact bladespreviously described. A conical surface 42 is formed on the end of thestem 39 opposite the cone 4G. The stem is extended into a mushroom-likeplate 43. At opposite ends of a diameter of the plate 43 there areformed axially extending supports 45 and 45' whose cross section isillustrated in Fig; 18. The-support 45 provides support to the rotorscanning brushes 50, I50, 250 andcontacts I5I, 25I intended forassociation with one of the outgoing lines brought to each vertical rowof stator contacts. The support 45' carries the rotor brushes andcontacts adapted for association with the other outgoing line of eachoutgoing stator azimuth. Thus the support 45 has embedded therein orotherwise afiixed thereto scanning brushes 5!], I 50 and 250 andcontactmembers 5I, I5I, 25I and 35I. The contacts 5|,

80 (Fig. 18) adapted to bring up against the stator electrodes I inmoving past them. This isschematically illustrated in "Fig.i19, in whichthe outgoing line stator elements having reference characterswhose lastdigit is "8 are in position to be engaged by lipped or. curled rotorbrushes and in' which. the scanning :brushes 50. etc.,; are. adjacent:to'platesshaped: members the A sternclutch plates 68.

last digit of whose reference characters is "I. The second support 45"similarly carries scanning brushes 50, I50 and 250' and galvanic contactelectrodes 5I', I5I', Iand I'.- Connection is provided between the rotorincoming line electrodes 4|, I4I, 24I and 34I on the one hand and thepairs of brushes and contacts 50, 5|; 5|, etc., by means of wiresembedded in the supports 45 and 45' andpassing through the cylindricalplate 43.

The driving mechanism for the rotor of the selector of the invention isillustrated in Fig. 16. A shaft 63 of steel or the like carries two setsof ball bearings 64 and 65.. The bearing 64 journals the shaft in thecone 24 and hence via the plate 22 the shaft is supported in theselector frame. Similarly the bearing 65 supports the shaft in the lowerstator flange 2, as indicated in Fig. 15. A cone 66 is drawn up tightagainst a shoulder 463 on the shaft by means of a ring 61. The cone 66therefore turns with the shaft. The ends of the shaft 53 are rectangularor hexagonal as indicated at II and engage with clutch plates 68. Coilsprings 69 are provided to expand the clutch plates outwardly from theselector for engagement with the corresponding clutch plates of theadjacent selectors in a column.

When the removable assembly shown in Fig.

' 16 is fastened together with its bank of stator lower flange 2 whereit is retained by means of the bearing cap 11, fastened to the flange bymeans of screws I8 (Figs; 2 and 15).

Fi 14 illustrates the engagement between adjacent selectors in a columnby means of the The plates 68 may have roughened surfaces II! to ensurethe transmission of rotation from the one shaft 63 to the next and so onthroughout the entire column. At one end of the column a prime moversuch as an electric motor transmits uniform rotation to the firstselector in the column.

With the selector so assembled, the rotor 20 of any one selector canturn with its shaft 63, or it may be held fast with respect to itsstator. The shaft 63 turns at all times at constant speed under thecontrol of a motor, notshown, which may beofconvent onal tyne. When aplurality of selectors according to the invention are assembled into acolumn, the motor is located at one end of the column and is connectedby clutch means to the shaft of the selector nearest it. Referring toFig. 16, while the selector is free, and during the process of 'linefinding. the coil 35 is de-energized, and the rotor 2n restsrof its ownweight on theconeifi by which it is centeredto carry its scanningbrushes 5n, 5M I50, I 5Il etc., uniformly past the plate-sha edidentification voltage electrodes of the outgo ng line stator bank.'Whenselection is ma e, the coil 35 is-energized. and rotor 2n isliftedby the action'of the resultant magnetic field on the cone 40 of ma neticmaterial. The cones 40 and 24 a ain assureproner centeringof, the rotor..A slightly greaterclearance,between the cones 24 and 'lothan-tnatbetween the pin-shaped outgoing line stator contacts such as 38,38', etc.,

(Fig. 19) and the rotor contact brushes I, SI,

. Fig. 19 illustrates the outgoing line contacts for one azimuth zorvertical'row in the stator bank and shows two output lines eachincluding seven contacts of which three are of fiat plate formtocooperate with the scanning brushes of the rotor and of which four maybe conventional round'pins for galvanic contact upon the stopping of therotor. The contacts of fiat plate form are Nos. 31, I31 and 231 for thefirst outgoing line and 31', I31 and 231' for the second outgoing line.The pin contacts are Nos. 38, I38, 238 and Y338 for the first outgoingline and 38", I38,'238' and 338' for the second outgoing line. v

The wires of the first outgoing line comprise wire 0, the busy conditiontest wire connected U, which is connected to contact 31, is held by thesource 86 at an alternating voltage of frequency ft characteristic ofthe units digit of the first line of the azimuth shown.

- The corresponding wires of the second outtionally be called the restposition, the rotor brushes sweep past the fixed contacts of the statorwithout galvanic contact with them. In Fig. 19, the stator contactsdesignated with primed reference characters are axially displaced withrespect to those with unprimed reference characters and similarly theprimed and unprimed rotor members are axially displaced with respect toeach other. With this construction each revolution of the rotor permitsscanning of a number of output lines equal to twice the number ofazimuth intervals provided on the stator.

In the description of operation of the selector of the invention now tobe given it will be assumed that the desired output line is the firstoutput line shown in Fig. 19, its conductors being designated A, B, T,O, and D and U. The alternating voltage sources 85, 85 and 86,86 of theazimuth shown, as well as those of other azimuths, are connected to arecording means I03 or sender as well as to the plate-shaped testelecgoing line are designated by the same capital letter referencecharacters with primes to distinguish them from the wires of the firstoutgoing line. Theyconnect respectively with stator outgoinglinecontacts of the same numbered reference characters, again primed. Thusthe source 85' generates and applies to the contact I3'I'- analternating voltage of a frequency ,fd characteristic of the tens digitof the second outgoingline of the azimuth shown, and the source 88'generates and applies to the contact 31' an alternating voltage offrequency is characteristic of the units digit of the second outgoingline for the azimuth shown. The incoming line includes four wires. Wire0 is the busy wire, grounded through the battery I04. Wire t is theduplicate selection test wire and a and b are the talking conductors.The wire 0 is connected to the stator incoming l-i-ne half-ring 33I andto its connected contact blade 332. Wire t is connected to half-ring 23land to contact blade 232, wire b to halt-ring I3I and to contact I32,and wire a lastly is connected to half-ring 3| and to contact blade 32.The rotor comprises ring 4| connected to two diametrically oppositepairs of brushes 50, 5I and 5I'. It also includes the ring I4I connectedto two diametrically opposite pairs of brushes I 50, I5I and I50. I5I;the ring 2 connected to two diametrically opposite pairs of brushes 250,25I and 250', 25!; and the ring 3 connected to two diametrically toopposite brushes 35I and 35I'.

As indicated in Fig. 19, where the rotor'is shown inthe axial positionwhich it occupies during continuous rotation, "which position may functrodes of their respective lines in the selector type described in mycopending application Serial No. 208,794 and the details of which formno necessary element of the present invention. For the description ofthe present invention it will suffice to state that in consequence ofthe dialing by calling subscriber the sender I03 chooses among theplurality of frequencies applied to it the frequencies is and fu. Itthen applies the frequency fd to the wire IN, and the frequency f to thewire I02.

An identification means 81, which may be'of the type described in mycopending application above referred to, includes two input terminals 88and 92 and an output terminal 96. The input 88 is connected to thearmature blade 89 of the relay I00 whose associated fixed contacts 90and SI are respectively connected to the talking conductors a and b ofthe selector incoming line. The input terminal 92 is connectedto thearmature contact 98 of relay I00 whose corresponding fixed contacts 94and 95 are respectively connected to the conductors IOI and I02. Theoutput terminal 98 is connected to the armature contact 91 of relay I00whose corresponding fixed contacts 98 and 99 are respectively connectedto the coil of relay I00 and to the wire 12 of the incoming line.

During rotation of the selector the brush I50, which is positioned twoazimuth intervals ahead of the other root brushes as shown in Fig. 20,scans the voltages of the various plate-shaped contacts of the rowrepresented by the contact I31. The potentials so scanned are appliedvia the wire b and contacts SI and 89 to the input terminal 88 of theidentification means. When the potential experienced by the brush I50 isof the same frequency as that applied to the input terminal 92 of theidentification means from the sender I03 via wire IN and contacts 94 and93 of relay I00, a D. C. voltage appears at the output terminal 96. Thisvoltage, applied through contacts 91 and 98 energizes relay I00 andconnects 5 the input terminal 88 to the wire a and input 92 to wire I02.

As the selector continues to rotate the brus 50, disposed one azimuthinterval in advance of the other rotor brushes, scans the voltages ofthe various outgoing line stator contacts in the row occupied by thecontact 31. The potentials so scanned are applied via wire a andcontacts 89 and of relay I00 to the input terminal 88 of theidentification means 81. When the voltage experienced by the brush 50 isof the same fre- 11 que i s; a tha aprliedt t e input term nal- 92 fromthe sender ill i via wire lllzyandcontacts 95 and ,3, a D. C. voltageappears) at the output terminal 95. This; I). C. voltageis applied viacontacts 91 and 99, of relay Hlfi to the wire t of the selcotorincomingline.

By virtue of, the contact existing between stator contacts 2,132 and"233 this voltage-is applied; across the, coil 35 and eifectsaxial'translationjoi the rotor in the sensepof the arrow 8|. Thus; theselector rotor is lifted offfthe cone -66'into engagement-with the cone24., (Fig. '16). In the coursexofithisgtranslation contactis madebetween 332 and3'3-33; to DliQvicle a holding circuit hythe coil3.5:3Via-theincon ing line Wire 0, battery i 2, and eponomizerresistance, I05. The cones 24 ndim nsase and o nt r h ot r in a busriipositionin whichit is atrest. In theflousy positiOn, tlig'lippedybrushes51, ll, 2.5+ and, 351 are respectively applied to the pinrshapedcontacts 5.. I38 23.8 am 338, or he iesired,out-goins line,The,lips;8ll;(1l?ig. l5) oithe brushestL 5,1 a d. 15 p event otati n of;t rotor past ihh esireda imuth. The incomin l ne a, at, o

sflm eq snfiy. sel anically extended to? the u going line A,-B, Qyia thecontact, established hetwesnilhandtat; I51 and 1' 3 251 n' 1Z38ad 351and, 3,38.

Apointer 82 (Figs. 1e; and 15) afilxeclto the cap 1 1 indicates theazimuthal position of the rotor while atresthy, reference for example toa -scale applied to the exterior cylindricalisurface 43 of the rotor.

What I claim is:

1 Aselector con prising a frame, a bank of ontgoing'linestator contactsarranged in vertical and horizontal, rows in a substantiallysemicylindrical inwardl facing array H fixed in the frame, all statorcontacts of each outgoing line being located in one vertical-rovrandeachof a plurality of outgoing lines connected to the se leotor havingin one horizontal row of. the bank a. oiuisnss la e-shap d Contact,each, of. a d lines, having in each of two "other horizontal rowsa ninrhe e s e w a uateinco i s line stator contacts supported coasially vithsaid array, two stator contactblades connected one o cash Mea en om in ar o ac annular electrorn g at supportedcoaxially with he a ra aera orrivin Shaft iqu na i n 1 @3 1 QQXEUY wi h said a re e l lm er ms meansonsaidshait, arotor including an arma,- tui'ea dapted tocooperate withsaigi magnet, said q i e y. en a ed id S el aid rotor being sh'apegltorest on saiclrotor supporting means with clearance fromsaid magnet, two.ring-shaped incoming line rotor contacts mount ed coaxially with therotor in position to rotate adjacent the arcuate inooming line statorcontactsr/hensaicl rotor rests on said supporting means, a scanningbrush connected to one of said incomingline-rotor contacts andsupportecl on the rotorin position toinov e pastthe condenserplate-shaped contacts of the bank when said rotor restson said rotorsupporting means, and an outgoing line rotor contact brush ccnneoteqtoeach of said incomingline rotor, contacts, said outgoing line rotorcontact brushes being ina single azimuth of the rotor displaoe clfrointho azimuth of said oanning brushby the interval) separating two or morevertical rows, in the bank, each of said outgoing line rotor contactbrushes being adapted upon energization of said,

magn t en a sa v ai al shepi contactof one of said other horizontalrowsin nemiesommie dr szmesns oea e he;

12 the bank, and; cache of. said incoming: line {rotor contacts-beingadapted;-uponenergization ofsaid magnet to engage'galvanically oneof;said con tact'blades. M

2. A selector comprising an outgoing line stator 'contactxbankconforming to a'substanti'ally semicylindrical. surface in which allelectrodes belonging to, any one outgoing. line arejarrahge'fl along aline parallel to the axis of thexsaiclisuriface, theelectrodesofrsaidbank belonging toone outgoing line includingiinadditiomto contacts for the talkingconductors or-the lineatqleast' oneelectrode of flat plate shape disposed::substan:- tiallyjperpendicularto) the axlsgoft the sai'dysur: face; and, adapted: to form one :of, theplates. offs condenser, a :pluralityrof selector incoming, line contactsofsemicircular, ring; shape; supported coaxially of the said surface, a.rotor mounted coaxially oil-the; saidhsurface for rotation relativetoijsaid. bankand for translation between first .an'd secondpositionsaxiallyiof said banlza plurality of. ring-shaped electrodes amazed-t0the. rotor in position to move in planes adjacent,thef planes or theselectorsincominsjline contactsiibut without contact thcrezwiflsh uponrotation ofothe.

rotorwhenvin its first axial position, a cann ns; brushof flat-plate,shape adapted toiormyoneoj. the plates of; a. condenser, said brush,being sup? ported, on, the rotor in; position, to :sweep; past theflflat plate electrodeszof, the; bank; but without .QQn? tact withQsaidflatiplateelectrodes uponrotation of the rotor WhfitkinitSQfiISjLfiKbJ-lDQSitiQll; said. scanning brush being, connected, to;one; of v ring-shaped, rotorelectrod s; iii-p urality, f sale vaniccontact brushes. 5111 11 1liedv one theirotor in pos ti to e f t; salranie ontact wi h; ont cts: of; the bank upon axiaitranslationoithepriotot from its first to its second axialapositiorr, said, contactbrushes being; each connectedto: oneof sa d, i se-s aped; le tr des;drivin means; n: easi g he: rotorttin; i sfirst: axi osition-1 eamstater thet same, andamean itatrans atei hermal: axially fr maitsfirst, tits-secondyax ali position; A, sel c or. omm sinswa ank: of..- out o nne tato c tact disnos iqve a. nortionaot a1 i cular li drical; urface, vca rows a all a dl e hor ontal r ws per end cul i= he. a of a la u ace.the. cQntaQ s'QfV-e eh out o n line bei sxarranseda a ins avert al w, arzonta a fapl t han gl le trodes int aid bank; t acont-acts-or, p 1 l t 0ot er, o i ntalrow e resn t, 'Qnnec esiw to; t talking o ducto soi .luli roioutsqixia, n s a p u a ty ,o nz ming1ine tamr contac at least; two0f: WhiC fil of ,arcuatashapedis? p sedtcoa i aidi rf qe Mot mqu iesi:

oaxiauyoi saidisu ace for, rotatiq relat elw s idrbank a ia fom an latqn Home, fi st ma c nd a ial osi on e a v o aid ban a; p u li of. comi aine o q i QQn ia 1- iz c ular ring shape supported on therotorcoaxially, of said surface, a; rotorgscanning, 'bILUSh COQI-i neted-i0 o e, o a d. n qm nse' ier oio o r t a lu a i o out n n t Ame-ta bus e onn cted s li e onei i dr iicqminsr oiq wh n nd e, r t ocat on. anda s, lation means; a ,apteclr o;move;th e rotor-axially,

and t ns' st i iem, a aqriviasi aean r he;

roto a t on acts n sh s po d:

therein: being so' 'elii'riensionecl, that when s without, galvaniq contct, withan s tact;sai ,rororjscmngh hislihe t A plays the stator bankand said incoming linerotor contacts rotating respectively adjacentsaidarcuate incomingiline stator contacts..

stator contacts arranged in vertical and horizon-,

tal rows in a substantially semicylindrical inwardly facing array, eachvertical row including all the outgoing line stator contacts for twooutgoing lines and including two contacts of plate shape, one for eachof said lines, and further including four pin-shaped contacts, two. foreach of said lines, two'incoming line stator electrodes of semicircularring shape supported coaxially with said array, two contact bladesconnected one to each of said incoming line stator electrodes, a rotormounted for rotation coaxially with the array and for translation withrespect thereto between first and second axial positions, two incomingline rotor electrodes of circular ring shape mounted in the rotorcoaxially therewith and positioned to rotate adjacent the incoming linestator electrodes when the rotor is in its first axial position, twodiametrically opposite rotor scanning brushes connected to each otherand to one of the incoming line rotor electrodes and axially displacedfrom each other in position to rotate with the rotor each past one ofthe horizontal rows of plate-shaped contacts in the array when the rotoris in its first axial position, a first pair of outgoing line rotorcontact brushes axially spaced apart by the separation of at least twohorizontal rows of pin-shaped contacts in the array and connected eachto one of the incoming line rotor electrodes, a second pair of outgoingline rotor contact brushes diametrically opposite the first, the contactbrushes of said second pair being axially separated by the spacing ofthe other two horizontal rows of pinshaped contacts in the array andconnected each to one of the incoming line rotor electrodes, drivingmeans to rotate the rotor, and means to lift the rotor from its first toits second axial position and to disengage it from the driving means,whereby when said rotor lifting means is not actuated the rotor turnswith the driving means without galvanic contact between any electricalstator element and any electrical rotor element, and whereby uponactuation of said rotor lifting means said incoming line rotorelectrodes are stressed against said contact blades and said outgoingline rotor contact brushes are stressed against pin-shaped contacts ofthe array.

5. A selector comprising a plurality of outgoing line stator contactpanels of plastic material each including a plurality of contactsconnected to multipling wires, said contacts including at least onesalient electrode of fiat plate shape and at least two salient contactpins, upper and lower slotted frame members adapted to support thepanels in a substantially semicircular array with said contacts on theinner surface of the semicylinder, conducting metallic foils interposedbetween adjacent panels, an annular electromagnet fastened to the upperof said frame members, a drive shaft journaled in the magnet and in thelower of said frame members coaxially with said array, a cone affixed tosaid shaft below the magnet, a rotor loosely fitting about said shaftbetween said magnet and said cone, a collar of magnetic material affixedto said rotor adjacent said magnet, a plurality of incoming line statorelectrodes of semicircular ring shape supported from said magnetcoaxially with regard to said shaft, a plurality of ringshaped incoming:line. rotor"el'e'ctrodes, a rotor -scanning brush connected toon'e ofsaid incom- -:=ing' line rotor'electrodes', and two rotor contactbrushes, said rotor scanning and contact brushes being so'dimensionedthat when said magnet is not energized the incoming line rotorelectrodes rotate respectively adjacent the incoming linestatorelectrodes with the scanning brush sweeping. past the plate-shapedoutgoing line stator electrodes, all without galvanic contact betweenelements of the rotor and stator, whereas upon energization of saidmagnet the rotor is lifted from the cone and stopped with the contactbrushes in contact'with outgoing line stator con tact pins and with theincoming line rotor electrodes in contact with incoming line statorelectrodes.

6. A selector comprising a'frame, a bank of outgoing line statorcontacts arranged in at least three horizontal rows and in a pluralityof vertical rows in a substantially cylindrical inwardly facing arrayfixed in the frame, one of said horizontal rows including contacts ofsubstantially flat plate shape adapted to act as condenser plates, twoarcuate incoming line stator contacts supported coaxially of said array,an electromagnet supported from the frame, a rotor driving shaftjournaled in the frame coaxially of the array, rotor supporting meansarranged on the shaft, a rotor including an armature adapted tocooperate with the magnet, the rotor being freely engaged on said shaftand being shaped to rest on said supporting means with clearance betweensaid armature and magnet, two ringshaped incoming line rotor contactsmounted coaxially of the rotor, a scanning'brush in the rotor connectedto one of said incoming line rotor contacts, and two outgoing line rotorcontacts in the rotor connected each to one of said rotor incoming linecontacts, said brush, rotor outgoing line contacts and rotor incomingline contacts being so positioned in the rotor that when said rotorrests on said supporting means said brush rotates with clearance pastthe contacts of said one horizontal row to form condensers therewithsuccessively, said rotor outgoing line contacts rotate past the contactsof said other two horizontal rows without galvanic contact therewith,and said rotor incoming line contacts rotate past said stator incomingline contacts to form condensers therewith continuously, and when saidmagnet is energized said rotor and stator incoming line contacts arebrought into galvanic contact and said rotor outgoing line contacts arebrought into galvanic contact with contacts of said other two horizontalrows.

'7. A selector comprising a bank of outgoing line stator contactsarranged in a plurality of vertical and in a plurality of horizontalrows in a substantially cylindrical inwardly facing array, one of saidhorizontal rows including contacts of fiat plate shape oriented parallelto right sections of the array, said contacts being adapted to formcondenser plates, a plurality of arcuate incoming line stator contactssupported coaxially of said array, an electromagnet supported in fixedposition relative to said array, a rotor driving shaft journaledcoaxially of the array, rotor supporting means on said shaft, a rotorincluding an armature adapted to cooperate with said magnet, said rotorbeing freely engaged on said shaft and shaped to rest on said supportingmeans with clearance between said armature and magnet, a plurality ofpairs of rotor contacts arranged in the rotor, each such pair includingEmma vmotorv outgoing, l ine; contact of; substantiallflflat plate. shp'el ozieuted perpendicularly tomheflax is of, the roton, said;rotonvoutgoingglipet 1 flat plate, shape; being adapted to, form-Icondonsers; with said; flat-Mata; 'shaped11 atanon out;

going line. oontaots; suoooasivelwflaim rotors: con,- tacts being-sopositionedq'ingsaids mimithat: when said-l rotor 1'6 StS,0n-.Said:SDQYfi-g meansq said rotor rotates with said z drivetshaitt without;vanicl contact betwflentmy *smton incoming-ling contaot and any; motor;cqntaptxand; withouttgal' vanic contact botweeniamoriotorx contact;angiz'any stator outgoing. 1in.-.,contact buttwith the platoshapedcontacts of the rotor movingwnasti the platershapod contaotstofythgtstatort closelm ad; a.- Qent herfito wher as; upon:onenzizattiorg of; said magnotlat leasttwo :notor lncomingwline contaotsengagggalvanicallytwozstattor incoming li-nmontacts and they.rotorsoutgoingi line; contacts tcom nectedpto said, twoqmtol:.incomingnli-net contacts engagegalvanically stator outgoinglinecontacts of; diiferent horizontal rows.

Re on np s it n ho filo o his-pate t

